Mailinglist Archive: opensuse (958 mails)

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Re: [opensuse] Paths of DNS Queries
On 2019-05-01 8:44 a.m., Carlos E. R. wrote:
Before that point (before reading from /etc/hosts) is the nscd intercept.
You mean that -- somehow, some unspecified manner -- that happens before the
decision as to whether to use files or DNS or something else as determined by
the nsswitch.conf file is accessed?

No, after the decision.

So you are saying that nsswitch.conf is accessed then ..

If the decision is files, it is nscd who answers what the files say.

HOW? you are doing the 'by magic' (aka unspecified) again.

"if the decision is 'files' ..."
well its not about 'decision.
if the refile reads:

hosts: files dns

that means 'try files first".
That means READING a file.
presumably /etc/hosts.

NOT invoking a routine or calling a network connection.


If the decision is bind, it is nscd who answers what the bind says.

More magic.
Its not about a 'decision', it is IF AND ONLY IF the 'files' returns
STATUS = notfound

And where does 'bind' come into this? I'm running dnsmasq, not Bind9.

I think you mean, reading the MAN(nsswitch.conf) where it says
"The order of the services on the line determines the order in which
those services will be queried, in turn, until a result is found."

So if the answer isn't find in "files" then it uses "dns".
But how does that get to invoke Bind9, nscd or dnsmasq?
In a deterministic, procedural manner?
As determined by some configuration!

Or, maybe it intercepts,

No, it's the beady-eyed raptor that intercepts ...

find out he doesn't know the answer,

You mean "its not in the cache".
I can see how that logic applies to both nscd and dnsmasq, but it still doesn't
say how it got to them in the first place.


lets the
call to the library continue, and when there is an answer it stores the
answer in the cache for the next time.

I think that "library continues" needs a LOT more clarification.
And yes, Bind9 and dnsmasq can be configured to do their own caching.
At which point the relevance of nscd becomes apropos.


--
A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting frowned upon?


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